The present invention relates to an electronic circuit in a motor vehicle, in particular in an instrument cluster in which various indicating instruments, indicating fields, monitoring and warning lights and possibly operating parts as well as electrical and electronic parts are arranged in a common housing and covered by a common transparent pane.
Such instrument clusters have been known for a long time, for instance from Federal Republic of Germany AS 16 05 947, and are used instead of the previously customary individual instruments in order to monitor various functions of an automobile.
Electrically controlled displays are increasingly used in such instrument clusters which, in addition to greater freedom of design, make a more intelligent and thus more precise and meaningful indication possible. The control is effected in general with the use of microprocessors or highly integrated, application-specific circuits. The digital pulse trains processed therein have very steep flanks and contain high-frequency portions up into the VHF-range, thus constituting a source of radio interference which makes radio reception or radio communication difficult when the motor vehicle is in operation. Such circuits can be affected furthermore by high-frequency radiation from the outside.
It has already been proposed (German patent application No. P 37 36 761.7) to provide a display computer and locate it on the common printed-circuit board in a housing which insulates from high-frequencies.
From Federal Republic of Germany OS 35 15 910 there is known, a high-frequency-proof housing with connecting pieces which serves to shield high-frequency parts, but the subject matter deals with a tap or distributor for cable television systems with a network of coaxial cables.